Float** internal representation (Numeric module)

[Jeff Epler]

a Python float() is a C "double", while I'm sure Numeric uses "float"
and "double" to match the C compiler.  The smallest C float different
from 1.0 is 1.0+(.5**23), and the smallest C double different from 1.0
is 1.0+(.5**52).  The smallest python float() different from 1.0 is also
1.0+(.5**52).

Jeff